Electrical musical instrument



Nov. 17, 1931. N. LAN GER ELECTRICAL MUSICAL INSTRUMENT Filed April 21,1950 2 Sheets-Sheet l J Wu 2 Sheets-Sheet 2 Filed April 21. 1930 nnoPatented Nov. 17, 1931 "UNITED STATES PATENT OFFICE NICHOLAS LANG-EB, OFBUDAPEST, HUNGARY, ASSIGNOR F TWO-THIBD'S TO JOHN EALMAGYI, OF BUDAPEST,HUNGARY nnno'mrcnz. MUSICAL insranunm' Application filed April 21, 1980,Serial No. 446,158, and in Hungary November 28, 1929.

My invention relates to electrical musical instruments of the type inwhich sounds are produced by means of electric oscillations.

It is an object of my invention to mprove an instrument of this type. Tothis end I provide instead of the usual thermoionic valvesglow-discharge lamps in connection with a source of current and asound-producing contrivance. I

Sound production in musical instruments by means of electricoscillations is an old roblem but as heretofore performed, to wit, Evmeans of thermoionic valves it involves the drawback that the cost andthe space requirements are prohibitive, for in instruments in whichthermoionic valves are employed, it is necessary to provide as manyvalves, each with its oscillatory circuit and other accessories, such ascapacities, inductances and the like, as there are sounds of variouspitches to be produced.

Another drawback of instruments having thermoionic valves is thedifiiculty ofproducing oscillations of adequate constancy, and thereforethe many attempts to provide a suitable musical instrument withthermoionic valves have failed.

By using'glow-discharge lamps instead of thermoionic valves, 1- obtain avery cheap, simple and small instrument. The production of electricoscillations by means of glowdischarge lamps is old, but it has neverbeen suggested to use such glow discharge lamps in connection with amusical instrument.

Glow-discharge lamps as manufactured at present are not quite suitablefor the production of electrical oscillations of adequate contions.However these difiiculties can be overcome by improving themanufacturing methods, particularly by saturating the electrodesthoroughly with the gas, before the bulb oi the lamp is sealed. By thesemeans the constancy of the oscillations is maintained.

The influences of electrostatic fields and temperature are eliminated bygrounded metal sheets surrounding the lamps.

In the drawings afixed to this specification and forming part thereofvarious diagrams of connections for an instrument embodying myinvention, and a glow-discharge lamp adapted for use in such aninstrument are illustrated diagrammatically by way of example.

in the drawings Fig. 1 is a diagram showing a glow-dis= charge lamp witha condenser and a resistance inserted in the lamp circuit, with thecondenser and the resistance connected in series,

Fig. 2 is a diagram showing asimilar circuit, with the condenser shuntedacross the resistance,

Fig. 3 illustrates a glow-discharge lamp,

Fig. 4 is a diagram of an instrument showing in combination seven of thecircuits illustrated in Fig. 1,

Fig. 5 is a diagram showing the combination of two circuits, each with aglow-discharge lamp, ior producing vibrating sounds, V

Fig. 6 is a diagram showing a lamp comhined with two resistances,

Fig. 7 is a diagram showing a circuit for musical instrument which isoperated Toy a tuned sheet, and

Fig. 8 is a diagram showing a circuit tor an instrument in which astring instrument is imitated.

Referring now to the drawings and first to Fig. l, B is a battery in acircuit containing a resistance R, a condenser C and a soundproducingcontrivance L, which may be a telephone, a loudspeaker or the like, andwhich will be referred to hereinafter as the telephone for the sake ofbrevity. G is a glow-discharge lamp which is connected in parallel withthe condenser C and the resistance R.

The condenser C may be designed for .0001 to 2.00 microfarads, theresistance R for .01 to 5.0 megohms and the battery B may supply directcurrent'of to 200 volts.

The condenser C is charged from the battery B through the resistance Rand, when the otential gradient between the termmals of t e condenserhas attained the lighting voltage of the lamp G, the current isdischarged through the lamp, and a sound is produced in the telephone L.The discharges through the lamp follow each other in ra 1d succession,and the frequency of the ischarges, and consequently also the itch ofthe sound which is produced in the te ephone, are a function of thecapacity of the conlenser, the ohmic value of the resistance R, thevoltage of the battery B and the properties of the lamp G. For a 'venlamp the pitch of the sound becomes higher when the voltage of thebattery B is increased or the capacity of the condenser C or the ohmicvalue of the resistance R is reduced. By suitably determining thevoltage, the capacity or the resistance it is possible to produce soundsof any desired p1tch.

Referring now to Fig. 2, this circuit contains. the same elements asdescribed with reference to Fig. 1, but the condenser-C is shuntedacross the resistance B. This cir-' As mentioned above, glow-dischargelamps offer the advantage of being cheaply and readily manufactured on aquantity production basis. y

Another advantage of glow-discharge lamps is that there are, so manyvariables available for varying the pitch of the currents produced. Thusthe capacity, the resistance and the voltage may be varied independentlyof each other, as described.

It is quite practicable to combine seventy or more glow-discharge lampswith their circuits in a musical instrument without incurringprohibitive cost or making the instru-. ment inconveniently large. Eachlamp with its circuit corresponds to a sound of a given pitch and thecircuits are connected to the same source of current and the same soundproducing contrivance by suitable keys which are preferably designedlike the keys ofapiano.

Preferably the glow-dischargelamps are subdivided into groups with thelamps of each groupsarranged' together in a. glass bulb, as illustratedin Fig. 3, where O is the glass bulb, E isa single electrode and'E 8 areindividual electrodes corresponding to seven glow-discharge lamps. N toN are the contact pins of the several electrodes.

Fig. 4 shows seven circuits such as illustrated in Fig. 1, each with acondenser C C, ance R B is the battery, and M is a otentiometer circuitwhich is connected wit the several lamp circuits so as to independentlyregulate the voltage for each circuit and to vary the frequency of theoscillations produced in each circuit. The resistances R of the severalcircuits are not connected directly with the telephone, transformers T Tbeing inserted between the resistances and the telephone, with theprimary windings P P connected with the resistances and the secondarywindings'S. S connected in series with each other and with the telephoneL, or preferably with an amplifier A, as the currents produced by thelamps are very weak. K K are keys connected with the primary windings Pof the several transformers and Q}. Q are contacts in the circuit of thebattery B, which are adapted to be connected with the keys.

The object of providing transformers between the several circuits andthe telephone a lamp G G and a resist- R' is to prevent reaction of theseveral circuits on each other, as might occur with the circuitsconnected directly with the telephone, in which case with severalcircuits operating at the same time, the sounds produced by them wouldbe somewhat distuned, which is obviously objectionable in a musicalinstrument.

The intensity of the sounds produced is regulated by the variableresistance Z at the amplifier A which is preferably operated by a pedal.

As a rule sounds of various pitches require various degrees ofamplification, as the human ear is not as sensitive for low-pitchedsounds as it is for high-pitched ones. Preferably an instrument issubdivided into three or fourgroups within its range of pitches, withashunt resistance intermediate each group and the amplifier forcompensating the differences of pitch. From the compensating resistancesthe current from each group is taken to a transformer having a primaryiwinding' for each group and a secondary winding common to all primarywindings. From this secondary winding the oscillations are transmittedto the amplifier. The instrument may be supplied with current from anysystem,.and'if it is supplied from an alternating current system, thecurrent is rectified before getting to the instrument.

An instrument of the type described not only affords all the musicalossibilities of a key instrument like a piano, ut also the ossibility ofproducing sounds of various timbres. The variation of the timbres may beeffected in various ways, for instance by means of loudspeakers or thelike of various timbres which are operated together or in succession.Besides, as in an organ, it is possible to couple the several circuitsso as brating sounds, as in a string instrument.

In string instruments the vibrating effect is brou ht about by touchingthe strings w th the ger in rapid succession so as to raise and lowerthe pitch of the sound. The circui'ts 1 and 2 each include aglow-discharge lamp, :1 source of current B, a condenser C, and atelephone L. T is a condenser inter mediate .the two circuits and eachcircuit contains a primary winding 11 and 22, re-

spectively, of the transformer. The two circuits are identical exceptfor the fact that the circuit 2-is tuned for normal pitch, while thecircuit 1 is tuned to a very low pitch at only 10 to oscillations persecond. The circuit thus produces alternating current of very lowfrequency which is transferred to the circuit 2 through the transformerT and causes slight periodical fluctuations of the directcurrent fromthe battery B in the circuit 2. As mentioned above, the pitch of thesound produced is influenced considerably by the voltage and, as thevoltage in the circuit 2 is varied, small periodical variations of thefrequency are produced, that is, a vibration effect is obtained.

'As mentioned above, the cost and size of the instrument are notprohibitive, notwithstanding the fact, that normally a lamp Gr isrovided for each pitch, making about 84 amps for an electric piano. Itmay, however, be desirable to cut down the number of lamps. Means foreffecting this are illustrated in Fig. 6. Instead of a single resistanceIt two resistances R--1 and R2 are provided, each with a key K1 and K2,respectively. With two resistances it is possible to produce sounds oftwo pitches with a single lam G in the circuit. Obviously means must eprovided for preventing simultaneous operation of the keys K-l and K 2and preferably the keys are spaced' from each other for a distancecorresponding to a. semitone, as this interval is required very rarely.

It is not necessary that keys of the normal type should be provided foran instrument according to my invention but preferably the keys are sodesigned that they are not depressed. Such keys may be fixed insulatedmetal plates or contacts of different colours, for instance nickelplates corresponding to thewhite and copper plates corresponding to theblack keys of a piano. The plates are connected with the respectivecircuits and to one terminal of the battery B, while the body of theoperator is connected to the other terminal of the battery, and theinstrument is played by touching the keys exactly like the keys of apiano, however without depresslng them. This operation is possible, asthe resistance of the human body can be neglected as compared with thatof the resistances R in several circuits. There is no danger from thecurrent, as it is only .2 to .3 milliamp. and the operator does not evenfeel it.

Fig. 7 shows a lamp circuit as described in combination with a ke K-1,which is operated by a tune sheet The tune sheet is moved by two rollers8 and 9 across a contact Q10, and contact is made when the key K1 entersa hole in the tune sheet.

In Fig. 8 the resistance R of the lamp circuit is arranged like thechord of a 1101'- mal chord instrument. A resistance of this kind may beobtained by winding about a thread of silk a very thin filament ofnichrome, about .05 mm. thick. A chord resistance made in this mannerand of the usual length amounts to 200,000 to 300,000 ohms. K1,K2 andK-3, are contacts connected with the battery B. In operation theoperator touches the resistance R with the fingers of the one hand whilewith the other hand he touches one of the contacts 12, 13, 14. In orderto obtain an effect which is still more similar to that of a chordinstrument, I may provide three or four chord resistances Rs, each witha lamp circuit of its own.

In accordance with this invention I can also obtain sound records fortalking machines and for wireless transmission directly from theinstrument. The instrument is operat-ed initially by electric energy andtherefore it is not necessary to transform the energy into sound wavesfor recording or transmitting, but the oscillations may be recorded ortransmitted directly. In this manner the necessity of converting soundWaves into electric energy and with it one of the worst causes ofdistortion is eliminated.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

In the claims afiixed to this specification no selection of anyparticular modification of the invention is intended to the exclusion ofother modifications thereof and the right'to subsequently make claim toany modification not covered by these claims is expressly reserved.

I claim 1-- 1. An electrical musical instrument com prising a circuitand asourc'e of current, a condenser, a resistance, a glow-dischargelamp, and a sound-producing contrivance, all in said circuit.

2. An electrical musical instrument comprising a circuit and a source.of current, a

resistance in series with said source of current,

a condenser, a glow-discharge lamp and a sound-producing contrivance,all in said circuit.

3. An electrical musical instrument comprising a circuit and a source ofcurrent a resistance, a condensershunted across sald resistance, a Qglow-discharge lamp and a sound-producing contrivance all in saidcircuit.

4. An electrical musical instrument comprising a circuit and a source ofcurrent, a resistance, a condenser, a glow-dlscharge lamp, a groundedshield surrounding said lamp, and a sound-producing contrivance, all insaid circuit.

5. An electric musical instrument comprising a plurality of circuits, asource of current, a sound-producing contrivance and a glow-dischargelamp and a resistanceand a condenser in each circuit, and a glass bulbsurrounding the electrodes of said glow-discharge lamps.

6. An electrical musical instrument comprising a plurality of circuits,each including a glow-discharge lamp and a resistance and a condenser, asource of current, a sound-producing contrivance, and means forconnecting said contrivance with all said circuits.

7. An electric musical instrument comprising a plurality of circuits,each including a glow-discharge lamp and a resistance an a condenser, asource of current, a sound-producing contrivance, means for connectinsaid contrivance with all said circuits, and an amplifier intermediatesaid circuit and said contrivance.

8. An electric musical instrument comprising a plurality of circuits,each including a glow-discharge lamp and a resistance an a condenser, asource of current, a sound-producing contrivance, means for connectingsaid contrivance with all said circuits, an amplifier intermediate saidcircuit and said contrivance said circuits being subdivided into groups,and means for equalizing the output of said groups arranged between saidcircuits and said amplifier.

9. An electric musical instrument comprising a plurality of circuits,each includin a glow-discharge lamp and a resistance and a condenser, asource of current, a sound-producing contrivance, means for connectingsaid contrivance with all said circuits, an amplifier intermediatesaidcircuit and said contrivance, and means for adjusting saidamplifier.

10. An electric musical instrument comprising a plurality of circuits,each including a glow-discharge lamp and a resistance and a condenser, asource of current, a soundproducing contrivance, a key-board connectedwith said circuits, and means for connecting said source with eachcircuit through the medium of said key-board.

operating said contrivances alternately and 7 simultaneously.

12. An electric musical instrument comprising a circuit, a source ofcurrent, a glowdischarge lamp adapted to produce oscillating currents, asoundroducing contrivance, a condenser a plurality of resistancesconnected to said condenser and to said lam and means for alternatelyconnectin said resistances with said lamp, all in said clrcuit.

13. An electric musical instrument comprising a plurality of circuits, aglow-discharge lamp and condenser in each of said circuits, a source ofcurrent for said circuits, a sound producing contrivance, a ke boardincluding a set of fixed and insulate plates each metal plate beingconnected with one of said circuits in such a manner that when touchedwith the fingers of an operator the circuit in question will be closedand the sound producing contrivance will be activated.

In'testimony whereof I afiix my s gnature.

NICHOLAS LANGER.

